Nothing else is opening wide this weekend and that’s always a sign that competing studios don’t want to go head to head with a picture they think will be doing big boxoffice business. “Oblivion’s” been tracking solidly with over-25 males and next best with under-25 males and over-25 females. That could put it into a high boxoffice orbit until May 3 when Disney and Marvel Studios’ sure-shot fantasy action adventure “Iron Man 3” blasts off. It’s already tracking through the roof in impressive double digits that make it a safe bet for a mega-blockbuster opening.

If “Oblivion” enlivens the multiplexes in April, it will re-energize Tom Cruise’s domestic boxoffice power following last December’s thriller “Jack Reacher,” which opened modestly to $15.2 million and wound up doing $80.1 million in U.S. and Canadian theatres. “Reacher,” however, performed much better internationally with about $136.5 million in ticket sales. That reflects Cruise’s ongoing international star power, which is already evident in “Oblivion’s” international release.

It’s very encouraging that “Oblivion” opened internationally last weekend to about $60 million in 52 territories, capturing first place in 48 of them. Cruise’s popularity abroad is particularly valuable now that the international marketplace is growing significantly and developing markets like China and Russia have become major sources of boxoffice revenue.

The Story: Jack Harper (Cruise) is one of the last remaining drone repairmen on a post-Apocalyptic Earth extracting vital resources after decades of war with terrifying aliens, the Scavs. Jack’s work is almost done when he rescues a beautiful stranger from a downed spacecraft, whose arrival puts humanity’s fate in Jack’s hands.

The Story: After a shocking terrorist act from within their own organization, the Enterprise’s crew is called back to Earth. Defying regulations and with a personal score to settle, Captain Kirk (Pine) leads his crew on a manhunt to capture an unstoppable destructive force and bring to justice those who are responsible.

Since “Star Trek” first took off in 1979 its 11 episodes have grossed about $1 billion in domestic theatres. The last one, the series reboot “Star Trek,” which Abrams also directed, opened May 8, 2009 to $75.2 million and took in $257.7 million domestically.

We’re back on a futuristic Earth May 31 when Universal, Blumhouse Productions and Platinum Dunes’ R rated sci-fi horror thriller “The Purge” arrives. Directed and written by James DeMonaco (“Little New York”), it stars Lena Headey, Ethan Hawke and Max Burkholder and is from “Paranormal Activity” producer Jason Blum.

The Story: In an America of the future, the government controls crime by allowing one night a year when all criminal activity including murder is legal and the public regulates itself with no thought of punishment. When an intruder enters the locked down community where James Sandin (Hawke) lives with his wife Mary (Headey) and their kids, what follows threaten to tear apart a family desperately trying to make it through the night.

The Story: A thousand years after mankind’s escape from Earth to the planet Nova Prime, General Cypher Raige (Will Smith) returns home after a long tour of duty to his young son (Jaden Smith). After an asteroid storm forces them to crash on a now deadly Earth, the General is dying and his son must cross hostile terrain to recover their rescue beacon, thereby achieving his dream of becoming a soldier like his father.

After “After,” sci-fi takes a month long break in favor of fantasy adventures like the Superman franchise 3D reboot “Man of Steel” (June 14) and the 3D Zombie Apocalypse tale “World War Z” (June 21) and action dramas like “White House Down” (June 28) and “The Lone Ranger” (July 3).

But fear not, sci-fi will be back in the boxoffice loop again July 12 with Warner Bros. and Legendary Pictures’ 3D action adventure “Pacific Rim.” Directed by Guillermo del Toro (“Hellboy” franchise), it stars Charlie Hunnam, Idris Elba and Charlie Day.

The Story: When the monstrous Kaiju rose from the sea, a deadly war began, consuming humanity’s resources for years on end. To fight them, a unique weapon was devised — giant robots controlled by two pilots, their minds locked in a neural bridge. Nearing defeat, man’s last hope is a washed up former pilot (Hunnam) and an untested trainee (Rinko Kikuchi).

The Story: In the year 2154 there are two classes of people — the super rich, who live on the pristine man-made space station Elysium, and everyone else, who live on an overpopulated, ruined Earth. Secretary Rhodes (Foster) is a government official who will stop at nothing to enforce anti-immigration laws and preserve the luxurious lifestyle of Elysium’s population. But that doesn’t stop those on Earth from trying to get in by any means they can.

When Max (Damon) finds himself backed into a corner, he agrees to take on a daunting mission that could save his life while bringing equality to the two polarized worlds.

Blomkamp’s “District 9,” which cost only $30 million to produce, opened Aug. 14, 2009 to a hefty $37.4 million. It went on to gross $115.6 million domestically. It also received four Oscar nominations, including best picture, adapted screenplay, film editing and visual effects.

Bottom line:The summer may end, but sci-fi will live on. In fact, the fall’s first post-Labor Day weekend will see Universal, One Race Productions and Radar Pictures’ Sept. 6 launch of the R rated sci-fi thriller “Riddick.”

Directed by David Twohy (“The Chronicles of Riddick”), it stars Vin Diesel and Karl Urban, both of whom starred in Twohy’s 2004 “Chronicles,” and Katee Sackhoff.

“Chronicles” opened June 11, 2004 to $24.3 million and ended up grossing $57.8 million in domestic theatres.

“Riddick” will mark Diesel’s third time playing the title role. He originally starred as Riddick in Twohy’s 2000 sci-fi thriller “Pitch Black.” After opening Feb. 18, 2000 to $11.6 million, “Pitch” went on to do $39.2 million domestically.

In “Riddick” Diesel’s in trouble fighting alien predators on a sun scorched planet until he’s rescued by someone from his past.